/*

 * Licensed to the Apache Software Foundation (ASF) under one

 * or more contributor license agreements.  See the NOTICE file

 * distributed with this work for additional information

 * regarding copyright ownership.  The ASF licenses this file

 * to you under the Apache License, Version 2.0 (the

 * "License"); you may not use this file except in compliance

 * with the License.  You may obtain a copy of the License at

 *

 *     http://www.apache.org/licenses/LICENSE-2.0

 *

 * Unless required by applicable law or agreed to in writing, software

 * distributed under the License is distributed on an "AS IS" BASIS,

 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.

 * See the License for the specific language governing permissions and

 * limitations under the License.

 */

package com.bff.gaia.unified.runners.core.construction;



import com.bff.gaia.unified.sdk.coders.CannotProvideCoderException;

import com.bff.gaia.unified.sdk.options.PipelineOptions;

import com.bff.gaia.unified.sdk.transforms.PTransform;

import com.bff.gaia.unified.sdk.transforms.display.DisplayData;

import com.bff.gaia.unified.sdk.values.PCollection;

import com.bff.gaia.unified.sdk.values.PInput;

import com.bff.gaia.unified.sdk.values.POutput;

import com.bff.gaia.unified.sdk.values.PValue;

import com.bff.gaia.unified.sdk.values.TupleTag;



import java.util.Map;



/**

 * A base class for implementing {@link PTransform} overrides, which behave identically to the

 * delegate transform but with overridden methods. Implementors are required to implement {@link

 * #delegate()}, which returns the object to forward calls to, and {@link #expand(PInput)}.

 */

public abstract class ForwardingPTransform<InputT extends PInput, OutputT extends POutput>

    extends PTransform<InputT, OutputT> {

  protected abstract PTransform<InputT, OutputT> delegate();



  @Override

  public OutputT expand(InputT input) {

    OutputT res = delegate().expand(input);

    if (res instanceof PCollection) {

      PCollection pc = (PCollection) res;

      try {

        pc.setCoder(delegate().getDefaultOutputCoder(input, pc));

      } catch (CannotProvideCoderException e) {

        // Let coder inference happen later.

      }

    }

    return res;

  }



  @Override

  public Map<TupleTag<?>, PValue> getAdditionalInputs() {

    return delegate().getAdditionalInputs();

  }



  @Override

  public void validate(PipelineOptions options) {

    delegate().validate(options);

  }



  @Override

  public String getName() {

    return delegate().getName();

  }



  @Override

  public void populateDisplayData(DisplayData.Builder builder) {

    builder.delegate(delegate());

  }

}